1. Field of the Invention
This invention relates to a mining machine, and more particularly, to a mining machine which includes roof bolting apparatus which enables a plurality of roof bolts to be installed in a mine roof at predetermined locations above the mining machine while the mining machine is continually advancing into a face of the mine to remove material therefrom.
2. Description of the Prior Art
In continuous underground mining, mining machines dislodge material from a mine face and convey the dislodged material rearwardly to a receiver. The mining machine is designed to continuously advance and dislodge the material being mined, thus forming an entry or tunnel in the seam. It is not uncommon for the mining operation to be stopped at various times and the mining machine withdrawn from the entry in order to install roof supports.
Various types of roof bolters may be utilized for movement into the entry adjacent the mine face for installation of roof bolts. U.S. Pat. No. 2,771,273 discloses such a simple, portable roof drilling and bolting machine which could be used for this purpose. More recent mine roof bolting apparatus, such as those disclosed in U.S. Pat. Nos. 4,094,158 and 4,097,854, include a temporary roof support to insure the stability of the roof during installation of the roof bolts. U.S. Pat. No. 4,094,158 also includes a protective canopy to protect mine personnel during the roof bolting operation. U.S. Pat. No. 3,964,265 discloses a more sophisticated roof supporting apparatus for a roof drilling machine which includes a boom for positioning the drill against the roof. Similarly, U.S. Pat. Nos. 4,398,850 and 4,420,277 disclose portable mine roof drilling and bolting apparatus which include extensible and movable boom devices for directing the drilling and bolting member to a desired location on the mine roof.
While these and any number of other such portable roof drilling and bolting apparatus may be utilized to secure the roof above a mining area, they all require the mining machine to be temporarily moved during their operation. After the roof bolts are set, the roof drilling and bolting apparatus is withdrawn from the entry and the continuous mining machine is again moved into the entry into a position adjacent the mine face. The mining machine then continues to dislodge material until it exposes a section of unsupported roof. The mining operation is again interrupted while roof bolts are set in this section of unsupported roof. Clearly, any such interruption of the continuous mining operation does not utilize the capabilities of the continuous mining machine.
U.S. Pat. No. 3,268,258 discloses a surge device that is positioned behind a continuous miner having roof bolters mounted on the sides thereof. The surge device is moved under the tail conveyor of the mining machine a sufficient distance to allow the mining machine to continue to advance while the surge device remains stationary and the roof bolters set bolts in the roof. The surge device is then advanced to its original position under the tail conveyor of the mining machine. However, it is neither taught nor suggested that the surge device may be used to install roof bolts over the mining machine in an area that would tend to provide protection for the mining machine operator.
U.S. Pat. No. 3,493,058 discloses a roof drilling and bolting machine which is mounted on the side of a continuous mining machine. The roof bolter assembly includes a carriage with a bolter mast, a roof jack and a floor jack mounted thereon. The roof jack and the floor jack are arranged to provide temporary support between the roof and floor of the mine and to lock the bolter carriage in a fixed position during installation of the roof bolts. Since it is mounted on the side of the machine for limited relative longitudinal movement between the machine and the bolter assembly, the bolter assembly remains stationary during installation of the roof bolts as the mining machine continues to dislodge material at the mine face. However, even though U.S. Pat. No. 3,493,058 discloses a system which improves the condition of a mine roof at either side of a continuous mining machine as it advances through the mine, there is no provision for supporting or improving the reliability of the roof directly above the mining machine as it continues to operate.
Another prior art mining machine has a T-shaped frame with ground engaging traction means located centrally of the frame and appears to be used in conjunction with a surge vehicle at the narrow, rear end thereof. The wider, forward end supports a drum type mining head which dislodges material from the face of the mine. The dislodged material is collected and transported rearwardly by a conveyor which passes over the ground engaging traction means to the surge vehicle. Roof bolting modules are located outwardly of the frame at opposite sides of the ground engaging traction means and appear to allow some roof bolts to be installed in the roof rearwardly of the drum type mining head.
Many prior art mining machines employ some type of material gathering device positioned rearwardly of and below the material disloding head. U.S. Pat. No. 2,613,800 discloses a material gathering device in which dislodged material which is gathered at the forward end of the machine is directed by rotating or oscillating arms onto a longitudinal conveyor means located centrally of the machine for transportation of the material rearwardly of the machine. While the longitudinal conveyor means of U.S. Pat. No. 2,613,800 is of a type which is generally referred to as a "universal" chain conveyor in the mining art, the mining machine disclosed U.S. Pat. No. 3,892,443 employs a short, longitudinally extending mat chain conveyor belt.
One prior art mining machine includes a boring head located on the extended end of a long, movable boom. A large gathering platform positioned below the boring head has a plurality of gathering arms which revolve around the upper surface thereof. The arms move transversely during a portion of each revolution around the gathering platform to deposit material onto a longitudinal conveyor at the side of the machine. However, since the large gathering platform requires more longitudinal space at the forward end of the machine than other types of gathering systems, it appears to be too large and to require the length of the machine to be increased too much to be a generally accepted alternative for use in many other types of mining machines.
Accordingly, there remains a need for a mining machine which includes roof bolting apparatus which is capable of installing a plurality of roof bolts at predetermined locations in a mine roof above the mining machine while the mining machine is continually advancing into a face of the mine to remove material therefrom.